Cannabidiol in Medical Marijuana: Research Vistas and Potential Opportunities.

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“The high and increasing prevalence of medical marijuana consumption in the general population invites the need for quality evidence regarding its safety and efficacy. Herein, we synthesize extant literature pertaining to the phytocannabinoid cannabidiol (CBD) and its brain effects.

The principle phytocannabinoid Δ9-tetrahydrocannabinol (Δ9-THC) and CBD are the major pharmacologically active cannabinoids. The effect of CBD on brain systems as well as on phenomenological measures (e.g. cognitive function) are distinct and in many cases opposite to that of Δ9-THC.

Cannabidiol is without euphoriant properties, and exerts antipsychotic, anxiolytic, anti-seizure, as well as anti-inflammatory properties.

It is essential to parcellate phytocannabinoids into their constituent moieties as the most abundant cannabinoid have differential effects on physiologic systems in psychopathology measures. Disparate findings and reports related to effects of cannabis consumption reflect differential relative concentration of Δ9-THC and CBD.

Existing literature, notwithstanding its deficiencies, provides empirical support for the hypothesis that CBD may exert beneficial effects on brain effector systems/substrates subserving domain-based phenomenology. Interventional studies with purified CBD are warranted with a call to target-engagement proof-of-principle studies using the research domain criteria (RDoC) framework.” https://www.ncbi.nlm.nih.gov/pubmed/28501518

http://www.sciencedirect.com/science/article/pii/S1043661817303559

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Improved Social Interaction, Recognition and Working Memory with Cannabidiol Treatment in a Prenatal Infection (poly I:C) Rat Model.

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“Neuropsychiatric disorders such as schizophrenia are associated with cognitive impairment, including learning, memory and attention deficits. Antipsychotic drugs are limited in their efficacy to improve cognition; therefore, new therapeutic agents are required.

Cannabidiol (CBD), the non-intoxicating component of cannabis, has anti-inflammatory, neuroprotective and antipsychotic-like properties, however, its ability to improve the cognitive deficits of schizophrenia remains unclear. Using a prenatal infection model, we examined the effect of chronic CBD treatment on cognition and social interaction.

CBD treatment significantly improved recognition, working memory and social interaction deficits in the poly I:C model, did not affect total body weight gain, food or water intake, and had no effect in control animals.

In conclusion, chronic CBD administration can attenuate the social interaction and cognitive deficits induced by prenatal poly I:C infection.

These novel findings present interesting implications for potential use of CBD in treating the cognitive deficits and social withdrawal of schizophrenia.”

https://www.ncbi.nlm.nih.gov/pubmed/28230072

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A systematic review of the effect of cannabidiol on cognitive function: Relevance to schizophrenia.

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“Cognitive impairment is a core symptom domain of schizophrenia, neurological disorders and substance abuse. It is characterised by deficits in learning, memory, attention and executive functioning and can severely impact daily living.

Antipsychotic drugs prescribed to treat schizophrenia provide limited cognitive benefits and novel therapeutic targets are required. Cannabidiol (CBD), a component of the cannabis plant, has anti-inflammatory and antipsychotic-like properties; however, its ability to improve cognitive impairment has not been thoroughly explored. The aim of this systematic review was to evaluate preclinical and clinical literature on the effects of CBD in cognitive domains relevant to schizophrenia.

CBD improves cognition in multiple preclinical models of cognitive impairment, including models of neuropsychiatric (schizophrenia), neurodegenerative (Alzheimer’s disease), neuro-inflammatory (meningitis, sepsis and cerebral malaria) and neurological disorders (hepatic encephalopathy and brain ischemia). To-date, there is one clinical investigation into the effects of CBD on cognition in schizophrenia patients, with negative results for the stroop test. CBD attenuates Δ9-THC-induced cognitive deficits.

 

The efficacy of CBD to improve cognition in schizophrenia cannot be elucidated due to lack of clinical evidence; however, given the ability of CBD to restore cognition in multiple studies of impairment, further investigation into its efficacy in schizophrenia is warranted. Potential mechanisms underlying the efficacy of CBD to improve cognition are discussed.”

https://www.ncbi.nlm.nih.gov/pubmed/27884751

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Cannabidiol as a Potential New Type of an Antipsychotic. A Critical Review of the Evidence

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“There is urgent need for the development of mechanistically different and less side-effect prone antipsychotic compounds.

The endocannabinoid system has been suggested to represent a potential new target in this indication.

Although, results from animal studies are inconsistent to a certain extent and seem to depend on behavioral paradigms, treatment duration and experimental conditions applied, cannabidiol has shown antipsychotic properties in both rodents and rhesus monkeys.

After some individual treatment attempts, the first randomized, double-blind controlled clinical trial demonstrated that in acute schizophrenia cannabidiol exerts antipsychotic properties comparable to the antipsychotic drug amisulpride while being accompanied by a superior, placebo-like side effect profile.

As the clinical improvement by cannabidiol was significantly associated with elevated anandamide levels, it appears likely that its antipsychotic action is based on mechanisms associated with increased anandamide concentrations.

The antipsychotic potential of cannabidiol has been investigated in various behavioral paradigms and different animal models of aspects of schizophrenia.

Although the results were partially inconsistent, they indicate that cannabidiol treatment ameliorates impairments of PPI, social interaction behavior and cognition in rodents and rhesus monkeys.

In addition, individual treatment attempts as well as one randomized, double-blind clinical study, demonstrated the antipsychotic potential of cannabidiol and its superior side effect profile compared to conventional antipsychotics. In addition, a recently conducted clinical trial investigating cannabidiol as an add-on medication showed promising results, although these have not yet been published in a peer reviewed process.

Obviously more clinical trials are needed to substantiate the current findings, and in particular to investigate long-term efficacy and safety in larger cohorts.

However, cannabidiol seems to represent a mechanistically different and less side-effect prone antipsychotic compound for the treatment of schizophrenia, even though the underlying pharmacological mechanisms are still under debate.

Nevertheless, the association between increased anandamide levels and reduced psychotic symptoms in schizophrenic patients treated with cannabidiol, points to a potentially new antipsychotic mechanism of action involving anandamide.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5099166/

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Cannabidiol is a partial agonist at dopamine D2High receptors, predicting its antipsychotic clinical dose.

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“Although all current antipsychotics act by interfering with the action of dopamine at dopamine D2 receptors, two recent reports showed that 800 to 1000 mg of cannabidiol per day alleviated the signs and symptoms of schizophrenia, although cannabidiol is not known to act on dopamine receptors. Because these recent clinical findings may indicate an important exception to the general rule that all antipsychotics interfere with dopamine at dopamine D2 receptors, the present study examined whether cannabidiol acted directly on D2 receptors, using tritiated domperidone to label rat brain striatal D2 receptors. It was found that cannabidiol inhibited the binding of radio-domperidone with dissociation constants of 11 nm at dopamine D2High receptors and 2800 nm at dopamine D2Low receptors, in the same biphasic manner as a dopamine partial agonist antipsychotic drug such as aripiprazole. The clinical doses of cannabidiol are sufficient to occupy the functional D2High sites. it is concluded that the dopamine partial agonist action of cannabidiol may account for its clinical antipsychotic effects.”

https://www.ncbi.nlm.nih.gov/pubmed/27754480

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Cannabidiol Prevents Motor and Cognitive Impairments Induced by Reserpine in Rats.

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“Cannabidiol (CBD) is a non-psychotomimetic compound from Cannabis sativa that presents antipsychotic, anxiolytic, anti-inflammatory, and neuroprotective effects.

In Parkinson’s disease patients, CBD is able to attenuate the psychotic symptoms induced by L-DOPA and to improve quality of life.

Repeated administration of reserpine in rodents induces motor impairments that are accompanied by cognitive deficits, and has been applied to model both tardive dyskinesia and Parkinson’s disease.

The present study investigated whether CBD administration would attenuate reserpine-induced motor and cognitive impairments in rats.

Our data show that CBD is able to attenuate motor and cognitive impairments induced by reserpine, suggesting the use of this compound in the pharmacotherapy of Parkinson’s disease and tardive dyskinesia.”

https://www.ncbi.nlm.nih.gov/pubmed/27733830

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The Influence of the CB1 Receptor Ligands on the Schizophrenia-Like Effects in Mice Induced by MK-801.

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“A growing body of psychiatric research has emerged, focusing on the role of endocannabinoid system in psychiatric disorders.

For example, the endocannabinoid system, via cannabinoid CB (CB1 and CB2) receptors, is able to control the function of many receptors, such as N-methyl-D-aspartate (NMDA) receptors connected strictly with psychosis or other schizophrenia-associated symptoms.

The aim of the present research was to investigate the impact of the CB1 receptor ligands on the symptoms typical for schizophrenia.

The present findings confirm that endocannabinoid system is able to modify a variety of schizophrenia-like responses, including the cognitive disturbances and hyperlocomotion in mice.

Antipsychotic-like effects induced by CB1 receptor antagonist, obtained in our research, confirm the potential effect of CB1 receptor blockade and could have important therapeutic implications on clinical settings, in the future.”

http://www.ncbi.nlm.nih.gov/pubmed/27577742

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A new antipsychotic mechanism of action for cannabidiol

Totally dope! – A new antipsychotic mechanism of action for cannabidiol, by Anand Gururajan

“The pharmacological strategy for the treatment of schizophrenia has not changed in the six decades since chlorpromazine was introduced in 1952. Although several newer agents have recently gained approval, the mechanism of action of antipsychotics is still largely based on normalising dopaminergic neurotransmission which does not adequately address the symptomatology of a very complex disorder. Moreover, they cause side effects such as extrapyramidal motor symptoms and metabolic syndrome which can worsen the patient condition.

In this regard, preclinical and clinical studies since the ’90s have demonstrated the antipsychotic potential of cannabidiol (CBD), a derivative of the cannabis sativa plant which does not have the adverse psychoactive properties of tetrahydrocannabinol.

In particular, CBD has been shown to be effective in attenuating the positive symptoms of schizophrenia with a negligible side-effect profile.

Accumulating evidence implicates dysfunction of the mammalian target of rapamycin (mTOR) signaling cascade in the pathophysiology of schizophrenia. Thus, in a recent paper, Renard et al. (2016) used the amphetamine (AMPH)-sensitisation protocol in rats to investigate whether the antipsychotic effects of CBD were mediated by its effects on the mTOR cascade. Specifically, they focused on the nucleus accumbens shell (NASh) which has been implicated as a therapeutically relevant ‘hot-spot’ for antipsychotic action and is one of the brain regions targeted by CBD.

Thus, together with the fact that CBD alone had no behavioural effects, the behavioural findings reinforce the potential utility of this cannabinoid as an antipsychotic for the treatment of the positive symptoms of schizophrenia.”

http://medicalxpress.com/news/2016-08-antipsychotic-mechanism-action-cannabidiol.html

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Cannabinoids in bipolar affective disorder: a review and discussion of their therapeutic potential.

“Bipolar affective disorder is often poorly controlled by prescribed drugs.

Cannabis use is common in patients with this disorder and anecdotal reports suggest that some patients take it to alleviate symptoms of both mania and depression.

We undertook a literature review of cannabis use by patients with bipolar disorder and of the neuropharmacological properties of cannabinoids suggesting possible therapeutic effects in this condition.

No systematic studies of cannabinoids in bipolar disorder were found to exist, although some patients claim that cannabis relieves symptoms of mania and/or depression.

The cannabinoids Delta(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD) may exert sedative, hypnotic, anxiolytic, antidepressant, antipsychotic and anticonvulsant effects.

Pure synthetic cannabinoids, such as dronabinol and nabilone and specific plant extracts containing THC, CBD, or a mixture of the two in known concentrations, are available and can be delivered sublingually.

Controlled trials of these cannabinoids as adjunctive medication in bipolar disorder are now indicated.”

http://www.ncbi.nlm.nih.gov/pubmed/15888515

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Fluorinated Cannabidiol Derivatives: Enhancement of Activity in Mice Models Predictive of Anxiolytic, Antidepressant and Antipsychotic Effects.

“Cannabidiol (CBD) is a major Cannabis sativa constituent, which does not cause the typical marijuana psychoactivity. However, it has been shown to be active in a numerous pharmacological assays, including mice tests for anxiety, obsessive-compulsive disorder, depression and schizophrenia. In human trials the doses of CBD needed to achieve effects in anxiety and schizophrenia are high. We report now the synthesis of 3 fluorinated CBD derivatives, one of which, 4′-F-CBD (HUF-101) (1), is considerably more potent than CBD in behavioral assays in mice predictive of anxiolytic, antidepressant, antipsychotic and anti-compulsive activity. Similar to CBD, the anti-compulsive effects of HUF-101 depend on cannabinoid receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27416026

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